T3W8
Round to the nearest 10, 100 or 1000:
99-100
199-200
39-40
999-1000
58-60
177-180
1119-1120
88-90
769-770
569-570
Multiply by 10, 100 and 1000:
1 x 1000=1000
2 x 60=120
7 x 700=490
6 x 50=300
100 x 40=4000
650 x 3=1950
190 x 2=380
40 x 40=1600
16 x 16=256
500 x 3=1500
Use rounding and compensating to multiply:
4 x 39= 4 x 40=160-4 =156
3 x 19=3 x 20=60-3=57
20 x 19=20 x 20= 400-20=380
100 x 99=100x100=10000-100=9900
7 x 29=7x30=210-7=203
16 x 9=16 x 10=160-16=144
0 x 999=0 x 10000=0-0=0
6 x 59=6 x 60=360-6=354
9 x 49=9 x 50=450-9=441
5 x 69=5 x 70=350-5=345
1. 1.34
2. 2.52
3.59 secs
WALT:instantly recall our basic facts.
I have timed my self three times to see how fast I can recall my basic facts.
Please give feedback.:D