Regrouping 21 ones are regrouped as 1 ten and 2 ones

Regrouping 21 ones are regrouped as 2 tens and 1 ones.

10
10
01
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21

I'll do the first one for you. it isn't very hard at all.on number one, you have (50 × 3), which equals 150, and (3 × 3), which equals 9. after you establish that, you add 150 and 9 together. so, (150 + 9) equals 159.this means that 53 × 3 = 159.