Mental Math Grade 6 Teacher's Guide

0.71 + 0.09 = 0.56 + 0.08 = 0.32 + 0.19 =
4.52 + 0.98 = 1.17 + 0.39 = 25.34 + 0.58 =
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The reinforcement activities for each strategy should be varied in
type and include frequent discussions. Progress should be
monitored and assessed in a variety of ways to help determine how
long students should spend on a particular strategy.
• Make 10s, 100s, or 1000s (Review)
Make 10 is a thinking strategy introduced in grade 2 for addition facts
which have an 8 or a 9 as one of the addends. It involves taking part of
the other number and adding it to the 8 or 9 to make a 10 and then
adding on the rest. For example, for 8 + 6, you take 2 from the 6 and
give it to the 8 to make 10 + 4. Students should understand that the
purpose of this strategy is to get a 10 which is easy to add.
Examples
a) For 58 + 6, think, “58 plus 2 (from the 6) is 60, and 60 plus 4 (the
other part of 6) is 64.”
b) For 350 + 59, think, “350 plus 50 is 400, and 400 plus 9 is 409.”
c) For 7400 + 790, think, “7400 plus 600 is 8000, and 8000 plus 190 is 8190.”
Practice Items
58 + 6 = 5 + 49 = 29 + 3 =
38 + 5 = 680 + 78 = 490 + 18 =
170 + 40 = 570 + 41 = 450 + 62 =
630 + 73 = 560 + 89 = 870 + 57 =
780 + 67 = 2800 + 460 = 5900 + 660 =
1700 + 870 = 8900 + 230 = 3500 + 590 =
2200 + 910 = 3600 + 522 = 4700 + 470 =
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Mental Math – Grade 6 31