1
40 + 30 = 70 4 + 3 = 70
400 + 300 = 700 2
40 - 30 = 10 4 - 3 = 10 400 - 300 = 100 3
46 + 30 = 76 4 + 3 = 76 4
46 - 30 = 16 4 - 3 = 16 5
16 + 11 = 27 16 + (10+1) = 27 316 + 11 = 327 6
16 + 9 = 25 16 + (+10-1) = 25
316 + 9 = 325 7
16 - 11 = 5 16 – (-10-1)= 5 8
16 - 9 = 7 16 - (-10+1) = 7
316 - 9 = 305 9
16 + 21 = 27 16 + (20+1) = 27 10
56 - 21 = 35 56 - (20-1) = 35 366 - 21 = 345 11
2 x 10 = 20 4 x 100 = 400 7 x 1000 = 7000 12
2 x 60 = 120 4 x 300 = 1200 7 x 6000 = 42000 13
27 x 10 = 270 46 x 100 = 4600 79 x 1000 = 79000 14
276 x 10 = 2760 467 x 100 = 46700 793 x 1000 = 793000 15
20 x 50 = 1000 400 x 70 = 28000 16
24 x 2 =48 4x2=8 2x2=4 17
25 x 2 =50 2 x 2 =4 4 +1 = 5 18
20 / 2 = 10 600 / 2 =300 19
42 / 2 = 21 4/2= 2 2/2= 1
20
642 / 2 = 321 6/2= 2 4/2= 1 2/2= 1
21
156 + 200 = 356 1 + 2 = 356 22
856 - 300 = 556 8-3=5 23
856 - 101 = 957 856 +100 +1 = 957 24
856 + 201 = 1057 856 +200 +1 = 1057 25