Strategies.

Mine & Dine Teacher Activity

WALT: Practice the strategies we have learn’t this term.

1. Use basic facts to work out these sums.

e.g. 40-30= is similar to 4-3=1, so 40-30= 10.

1. 10+50=is similar to 1+5=6,so 10+50=60
2. 90-40=is similar to 9-4=5,so 90-40=50
3. 30+20=is similar to 3+2=5,so 30+20=50

2. Make tens so work out these sums.

1. 6 + 2 + 4= 6+4 is a 10,a tidy number.Now there’s 2 left,10+2=12.
2. 1 + 2 + 5 + 7 + 9 + 5 + 3=1+9=10,5+5=10,7+3=10,10+10+10=30,nows there’s 2.30+2=32.
3. 30 + 60 + 70 + 40=Make a tidy number,30+70=100,60+40=100.100+100=200.

3. Go back through ten to work out these sums.

e.g. 15-7= Takeaway 5 from the seven which =10,now there’s 2.10-2=8

       15-5-2=15-5=10 and 2 left.10-2=8.

       10-2= 8+2=10 but if you take 2 away it’s just 8.

1. 15-6=take 5 from 6,15-5=10,now there’s 1 left.10-1=9
2. 20-5=15+5=20 but if you take 5 away it’s just 15.
3. 16-9=take 6 from 9,16-6=10,now there’s 3.10-3=7.

4. Solve sums with both addition and subtraction.

e.g. 4 + 2 + 5 - 9=

5 + 4 = 9, so I can ignore the 9 and the only number that is left is 2. The answer is 2.

1. 9 + 3 + 4 - 7 - 2=takeaway 9,3+4=7.The answer is seven.
2. 2 + 6 + 4 + 3 - 7=takeaway 6+4=10 cause 3-7=10,only 2 left.The answer 2.
3. 4 + 5 - 9=4+5=9,take it away

5. Make a tidy number to solve change unknown problems.

1. 77 + 3+3= 83
2. 56 +4+5=65
3. 68 + 2+5=75