Jar A has 28 marbles. Jar B has 12 more marbles than jar A. Jar C has twice as many marbles as jar B. How many marbles are there altogether?
Jar B has 28 + 12 = 
<gadget id="calculator">28+12</gadget>
<output>40</output>
40 marbles.
Jar C has 2 x 40 = 
<gadget id="calculator">2*40</gadget>
<output>80</output>
80 marbles.
Therefore, there are 28 + 40 + 80 = 
<gadget id="calculator">28+40+80</gadget>
<output>148</output>
148 marbles altogether.

<result>148</result>