Adding and subtracting on paper · Alberta Grade 6 · maddyhelps.com
Name
Date
Line the points up, one under the other, and work from the right. Every number here has two places after the point, so the columns all mean the same thing. Then do the two problems underneath.
Dollars
$24.75
+$9.60
$50.00
−$36.45
Metres
1.85
+2.40
3.00
−1.26
One trip to the shop
Price
Sketchbook
$8.49
Pack of pencils
$5.25
Eraser
$1.79
Roll of tape
$3.99
Total
You pay with a $20 bill. How much change?
A roll of ribbon is 5.00 m. You cut off 1.45 m, then 0.80 m. How much ribbon is left?
For the grown-up
Money and measurement
$24.75 + $9.60 = $34.35, $50.00 − $36.45 = $13.55; 1.85 + 2.40 = 4.25 m, 3.00 − 1.26 = 1.74 m. The shop: $19.52 spent, so the change from $20 is $0.48. The ribbon: 1.45 + 0.80 = 2.25 m cut off, and 5.00 − 2.25 = 2.75 m left. Taking them off one at a time works too: 5.00 − 1.45 = 3.55, then 3.55 − 0.80 = 2.75 m.
$50.00 − $36.45 is the one that stalls: the trade has to travel across both zeros, so the dollars lend to the dimes and the dimes lend to the cents. The other thing to watch is a number written with one decimal place and then lined up on the right, the way whole numbers are. Write $9.60 as $9.6 under $24.75 and the 9 lands in the dimes column, so it is added as $0.96 and the total comes out $25.71 instead of $34.35. Writing the place-holding zero is what keeps the columns honest.