diff --git a/gettingStarted/gettingStarted.tex b/gettingStarted/gettingStarted.tex
index f914c14..8df722a 100755
--- a/gettingStarted/gettingStarted.tex
+++ b/gettingStarted/gettingStarted.tex
@@ -10,78 +10,75 @@
 \end{abstract}
 \maketitle
 
-
 %% \begin{listObjectives}
 %%  \item{Determine a reasonable estimate before preforming a calculation.}
 %%  \item{Increase student confidence in their ability to solve difficult math problems by using previous results, trying different methods, asking questions, and work- ing with others.}
 %% \end{listObjectives}
 
 \begin{listOutcomes}
-\item{Edit/create PDFs to create completed journal entries.}
-\item{Hand-in journal entries online.}
-\item{Work in nonstandard units.}
-\item{Estimate areas and volumes in nonstandard units.}
-\item{Critique and dismantle reasonable hypotheses in regard to geometry and arithmetic.}
+  \item{Edit/create PDFs to create completed journal entries.}
+  \item{Hand-in journal entries online.}
+  \item{Work in nonstandard units.}
+  \item{Estimate areas and volumes in nonstandard units.}
+  \item{Critique and dismantle reasonable hypotheses in regard to geometry and
+              arithmetic.}
 \end{listOutcomes}
 
 \mynewpage
 
-
 \begin{question}
   Here's a scale picture of a large \textit{Happy Fun Ball}:
   \begin{center}
-  \begin{tikzpicture}
-  % Define the radius of the circle (half of the diameter)
-  \def\ballradius{4.7cm} % 
+    \begin{tikzpicture}
+      % Define the radius of the circle (half of the diameter)
+      \def\ballradius{4.7cm} % 
 
-  % Draw the circle
-  \draw[ultra thick] (0, 0) circle (\ballradius);
+      % Draw the circle
+      \draw[ultra thick] (0, 0) circle (\ballradius);
 
-  % You can add additional elements or labels here if needed
-  \end{tikzpicture}
+      % You can add additional elements or labels here if needed
+    \end{tikzpicture}
   \end{center}
-Look around our classroom. How many large \textit{Happy Fun Balls}
-would it take to:
-\begin{enumerate}
-\item Line one edge of the classroom?
- \item Cover the floor?
- \item Fill the room?
-\end{enumerate}
-In each case, EXPLAIN how you arrive at your conclusion.
+  Look around the room you are in. How many large \textit{Happy Fun Balls}
+  would it take to:
+  \begin{enumerate}
+    \item Line one edge of the room?
+    \item Cover the floor?
+    \item Fill the room?
+  \end{enumerate}
+  In each case, EXPLAIN what you are doing and how you arrive at your conclusion.
 \end{question}
 \mynewpage
 
-
-
-
-
 \begin{question}
-Small \textit{Happy Fun Balls} have a about one-third the diameter of a large \textit{Happy Fun Ball}. How many small \textit{Happy Fun Balls} would it take to:
-\begin{enumerate}
-\item Line one edge of the classroom?
-\item Cover the floor?
-\item Fill the room?
-\end{enumerate}
-In each case,  EXPLAIN how you arrive at your conclusion.
+  Small \textit{Happy Fun Balls} have a about one-third the diameter of a large
+  \textit{Happy Fun Ball}. How many small \textit{Happy Fun Balls} would it take
+  to:
+  \begin{enumerate}
+    \item Line one edge of the room?
+    \item Cover the floor?
+    \item Fill the room?
+  \end{enumerate}
+  In each case,  EXPLAIN what you are doing and how you arrive at your
+  conclusion.
 \end{question}
 \mynewpage
 
-
-
-
 \begin{question}
   Your friend and fellow student \textit{Geometry Giorgio} suggests
   that we think in the following way:
-\begin{quote}
-  Since a large \textit{Happy Fun Ball} has about three times the
-  diameter of a small \textit{Happy Fun Ball,} the answers for Problem
-  $2$ above should all be about three times the answers from Problem
-  $1$.
-\end{quote}
-Is \textit{Geometry Giorgio} correct?  If he is correct, explain
-why. If he is not correct, explain how you know he is not correct. 
+  \begin{quote}
+    Since a large \textit{Happy Fun Ball} has about three times the
+    diameter of a small \textit{Happy Fun Ball,} the answers for Problem
+    $2$ above should all be about three times the answers from Problem
+    $1$.
+  \end{quote}
+\begin{center}
+  \bf Is \textit{Geometry Giorgio} correct?
+\end{center}
+Check your answers from Problems 1 and 2 and use them to either \textbf{validate or invalidate}
+\textit{Geometry Giorgio}'s claim. Explain what you do and explain to us how your computations helps you determine if 
+\textit{Geometry Giorgio} is in fact correct or not.
 \end{question}
 
-
-
 \end{document}
diff --git a/journalOfGeometry.tex b/journalOfGeometry.tex
index 62ee398..5c1ebcc 100755
--- a/journalOfGeometry.tex
+++ b/journalOfGeometry.tex
@@ -38,6 +38,10 @@
 %%
 %%
 
+
+%% SIGNIFICANT DIGITS
+%% DIMENSIONAL ANALYSIS? A LA https://hapax.github.io/physics/teaching/hacks/napkin-hacks/
+
 %% \partstyle
 %% \activity{sectionHeads/sizeAndGrowthOfNumbers.tex}
 %% \journalstyle
@@ -102,8 +106,13 @@
 \activity{gettingStarted/gettingStarted.tex} %% DONE
 \checkstyle
 \activity{gettingStarted/checkYourself.tex} %% DONE
+
 \journalstyle
+\activity{significantFigures/significantFigures.tex} %% DONE
+\checkstyle
+\activity{significantFigures/checkYourself.tex} %% DONE
 
+\journalstyle
 \activity{roofEstimates/roofEstimates} 
 \checkstyle
 \activity{roofEstimates/checkYourself.tex} %% DONE  
diff --git a/nets/nets.tex b/nets/nets.tex
index 72c4524..19573b5 100644
--- a/nets/nets.tex
+++ b/nets/nets.tex
@@ -1,4 +1,4 @@
-\documentclass[noauthor,nooutcomes,hints,handout]{ximera}
+\documentclass[noauthor,nooutcomes,hints,handout,12pt]{ximera}
 
 \input{../preamble.tex}
 
diff --git a/paintedCubes/paintedCubes.tex b/paintedCubes/paintedCubes.tex
index 30e71b8..8195c3d 100644
--- a/paintedCubes/paintedCubes.tex
+++ b/paintedCubes/paintedCubes.tex
@@ -1,4 +1,4 @@
-\documentclass[noauthor,nooutcomes,hints,handout]{ximera}
+\documentclass[noauthor,nooutcomes,hints,handout,12pt]{ximera}
 
 \input{../preamble.tex}
 
diff --git a/significantFigures/checkYourself.tex b/significantFigures/checkYourself.tex
index 79b9f95..95205a6 100755
--- a/significantFigures/checkYourself.tex
+++ b/significantFigures/checkYourself.tex
@@ -11,78 +11,28 @@
 
 
 \begin{exercise}
-  Here is a picture of a person wearing a backpack:
-  \begin{center}
-    \includegraphics[width=3in]{backpack.jpg}
-  \end{center}
-  If their backpack was completely filled with ping pong balls, how
-  many ping pong balls would you suspect were in it?
-  \begin{enumerate}\begin{multicols}{2}
-    \item Tens of ping pong balls.
-    \item Hundreds of ping pong balls.
-    \item Thousands of ping pong balls.
-    \item Tens of thousands of ping pong balls. 
-    \end{multicols}
-  \end{enumerate}
+Round $6192600$ to $3$ significant digits. 
 \end{exercise}
 
 
 \begin{exercise}
-  If their backpack was completely filled with tennis balls, how many
-  tennis balls would you suspect were in it?
-  \begin{enumerate}\begin{multicols}{2}
-    \item Tens of tennis balls.
-    \item Hundreds of tennis balls.
-    \item Thousands of tennis balls.
-    \item Tens of thousands of tennis balls.
-    \end{multicols}
-  \end{enumerate}
+ Compute: $6.10\times 6271$
 \end{exercise}
-  
-
-
-\begin{exercise}
-  \textit{Chewbacca} is a $7.5$ foot tall wookie.
-  \begin{center}
-    \includegraphics{chewbacca.jpeg}
-  \end{center}
-  How much surface area does Chewbacca have?
-  \begin{enumerate}
-  \item Several square feet.
-  \item Tens of square feet.
-  \item Hundreds of square feet.
-  \item Thousands of square feet.
-  \end{enumerate}
-  \end{exercise}
-
 
 
 \begin{exercise}
-  Wookies have around $15000$ hair follicles per square inch of
-  skin. How many hairs do they have per square foot?
-  \begin{enumerate}
-  \item $6\times 15000$.
-  \item $12\times 15000$.
-  \item $36\times 15000$.
-  \item $72\times 15000$.
-  \item $144\times 15000$.
-  \end{enumerate}
+Compute: $150000\div 440.000$
 \end{exercise}
-
+  
 
 \begin{exercise}
-  Suppose there are $4,000,000,000$ Wookies in the universe. Do any
-  two wookies have the exact same number of hair follicles?
-  \begin{enumerate}
-  \item Definitely yes. %144*15000*10 < 4 billion
-  \item Maybe?
-  \item Definitely no.
-  \end{enumerate}
-  
+ Compute: $61100+4.4$
 \end{exercise}
 
+\begin{exercise}
+  Compute: $870000000 - 657000$
+  \end{exercise}
 
 
-
-\answerlistbox{(b)}{(a)}{(b)}{(e)}{(a)}
+\answerlistbox{$6190000$}{$38300$}{$340$}{$61100$}{$870000000$}
 \end{document}
diff --git a/significantFigures/significantFigures.tex b/significantFigures/significantFigures.tex
index 8df722a..ee25447 100755
--- a/significantFigures/significantFigures.tex
+++ b/significantFigures/significantFigures.tex
@@ -1,12 +1,11 @@
 \documentclass[handout,noauthor,nooutcomes,hints,12pt]{ximera}
 \input{../preamble.tex}
-\title{Getting started}
-\author{Claire Merriman and Bart Snapp}
+\title{Significant digits}
+\author{Bart Snapp}
 
 \begin{document}
 \begin{abstract}
-  We make estimates of numbers of objects in every-day settings and we
-  observe the effects of scaling when we change objects.
+We will not delude ourselves with a false sense of precision. 
 \end{abstract}
 \maketitle
 
@@ -16,69 +15,77 @@
 %% \end{listObjectives}
 
 \begin{listOutcomes}
-  \item{Edit/create PDFs to create completed journal entries.}
-  \item{Hand-in journal entries online.}
-  \item{Work in nonstandard units.}
-  \item{Estimate areas and volumes in nonstandard units.}
-  \item{Critique and dismantle reasonable hypotheses in regard to geometry and
-              arithmetic.}
+  \item Identify the number of significant digits in an expression.
+  \item Apply the rules of significant digits in addition, subtraction.
+  \item Apply the rules of significant digits in multiplication, and division.
+  \item{Reflect on past work.}
 \end{listOutcomes}
 
+\begin{description}
+  \item[Rules for determining the number of significant digits]\hfil
+\begin{itemize}
+    \item All nonzero digits are significant.
+    \item Zeros between nonzero digits are significant.
+    \item Leading zeros are not significant.
+    \item Trailing zeros are significant only if there is a decimal point.
+\end{itemize}
+    \item[Addition and Subtraction]\hfil
+    \begin{itemize}
+      \item The sum or difference should have the same number of decimal places as the measurement with the fewest decimal places.
+    \end{itemize}
+    \item[Multiplication and Division]\hfil
+    \begin{itemize}
+      \item The product or quotient should have the same number of significant digits as the measurement with the fewest significant digits.
+    \end{itemize}
+\end{description}
 \mynewpage
 
 \begin{question}
-  Here's a scale picture of a large \textit{Happy Fun Ball}:
-  \begin{center}
-    \begin{tikzpicture}
-      % Define the radius of the circle (half of the diameter)
-      \def\ballradius{4.7cm} % 
-
-      % Draw the circle
-      \draw[ultra thick] (0, 0) circle (\ballradius);
+  Let's see if you understand the rules above. Go to:
+\begin{center}
+  \url{https://chemquiz.net/sig/}
+\end{center}
+and quiz yourself!
+\begin{itemize}
+  \item Select 5 problems.
+  \item Select all types of questions: Counting sig figs in numbers, Rounding numbers by sig figs, Multiplication \& division problems with sig figs, Addition \& subtraction problems with sig figs.
+  \item Select decimal (regular) notation
+  \item Choose your thousands separator.
+  \item No units. 
+  \item Fill-in-the-blank
+  \item Start!
+\end{itemize}
+Take the quiz until you achieve a perfect score. 
 
-      % You can add additional elements or labels here if needed
-    \end{tikzpicture}
-  \end{center}
-  Look around the room you are in. How many large \textit{Happy Fun Balls}
-  would it take to:
-  \begin{enumerate}
-    \item Line one edge of the room?
-    \item Cover the floor?
-    \item Fill the room?
-  \end{enumerate}
-  In each case, EXPLAIN what you are doing and how you arrive at your conclusion.
+\textbf{BELOW, DESCRIBE A PROBLEM YOU MISSED OR THOUGHT WAS TRICKY.} 
 \end{question}
 \mynewpage
 
 \begin{question}
-  Small \textit{Happy Fun Balls} have a about one-third the diameter of a large
-  \textit{Happy Fun Ball}. How many small \textit{Happy Fun Balls} would it take
-  to:
-  \begin{enumerate}
-    \item Line one edge of the room?
-    \item Cover the floor?
-    \item Fill the room?
-  \end{enumerate}
-  In each case,  EXPLAIN what you are doing and how you arrive at your
-  conclusion.
+Demonstrate skill here by answering the following questions respecting significant digits. \textbf{In each case, explain your reasoning.}
+\begin{enumerate}
+  \item Compute: $32.8000 \cdot 7200$
+  \vfill
+
+  \item How many significant digits are in $191.000$?
+
+  \vfill 
+  \item Round  $3363750$ to $4$ significant digits.
+  \vfill
+
+  \item Compute:  $5290 - 0.3100$
+  \vfill
+  \item Compute: $87 900 000 + 10 000$
+\vfill
+\end{enumerate}
+
+
 \end{question}
 \mynewpage
 
 \begin{question}
-  Your friend and fellow student \textit{Geometry Giorgio} suggests
-  that we think in the following way:
-  \begin{quote}
-    Since a large \textit{Happy Fun Ball} has about three times the
-    diameter of a small \textit{Happy Fun Ball,} the answers for Problem
-    $2$ above should all be about three times the answers from Problem
-    $1$.
-  \end{quote}
-\begin{center}
-  \bf Is \textit{Geometry Giorgio} correct?
-\end{center}
-Check your answers from Problems 1 and 2 and use them to either \textbf{validate or invalidate}
-\textit{Geometry Giorgio}'s claim. Explain what you do and explain to us how your computations helps you determine if 
-\textit{Geometry Giorgio} is in fact correct or not.
+Let's reflect on the activity we did the previous class day. Express your answers from Problems 1 and 2 from that activity 
+respecting significant digits. Explain your reasoning. 
 \end{question}
 
 \end{document}
diff --git a/sineAndCosine/sineAndCosine.tex b/sineAndCosine/sineAndCosine.tex
index 99e9994..bcb4d74 100755
--- a/sineAndCosine/sineAndCosine.tex
+++ b/sineAndCosine/sineAndCosine.tex
@@ -1,4 +1,4 @@
-\documentclass[noauthor,nooutcomes,hints,,12pt]{ximera}
+\documentclass[noauthor,nooutcomes,hints,handout,12pt]{ximera}
 
 \input{../preamble.tex}
 
diff --git a/solarAngle/solarAngle.tex b/solarAngle/solarAngle.tex
index 7a5faa3..96cbfb2 100755
--- a/solarAngle/solarAngle.tex
+++ b/solarAngle/solarAngle.tex
@@ -130,7 +130,7 @@
   \item Why are the Sun's rays parallel?
   \item At each drawn point on the Earth above, we have drawn a stick
     pointing ``straight up.'' Moreover, we have labeled this with the
-    so-called ``solar zenith angle.'' Identify and mark the geometric
+    so-called ``solar zenith angle.'' Identify and mark a \textbf{human-measurable}
     angle that determines the value of the solar zenith angle.
   \item \textbf{Lines of latitude} are formed by making an angle from
     a desired position, to the center of the Earth, to the point on
diff --git a/sunAndShadows/sunAndShadows.tex b/sunAndShadows/sunAndShadows.tex
index 7570d0b..6c68d46 100755
--- a/sunAndShadows/sunAndShadows.tex
+++ b/sunAndShadows/sunAndShadows.tex
@@ -102,5 +102,6 @@
  \item The difference in the length of this shadow on the summer
    solstice and the winter solstice.
 \end{enumerate}
+In both cases, explain your reasoning and show work.
 \end{question}
 \end{document}