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Treat 72 as 70 + 2:
70 * 6 = 420
2 * 6 = 12
420 + 12 = 432
Equivalently, 6(70 + 2) = 432.
Theoretically, you can break 72 (or even 6) down into whatever you like, though it becomes harder instead of easier if you break the numbers into too many components. For instance, 6(10 + 10 + 10 + 10 + 10 + 10 + 10 + 2) = 432 as well, but adding 60 repeatedly is time-consuming and unhelpful. Breaking both down, you could try (4 + 2)(10 + 10 + 10 + 10 + 10 + 10 + 10 + 2) even, which might be good for someone who is only capable of very basic multiplication, but would expand to 40 + 40 + 40 + 40 + 40 + 40 + 40 + 8 + 20 + 20 + 20 + 20 + 20 + 20 + 20 + 4, which still = 432.
Basically, when breaking things down like this, use common sense to make the problem easier instead of harder.
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What strategy is used to multiply mentally?
Most people who multiply mentally are using some form of the distributive property. If you wanted to do something like 47 x 5 in your head, that's (40 x 5) + (7 x 5) = 200 + 35 = 235
How do you check 19 times 6 using the distributive property?
One way to do this is to write 19(6)=(20-1)6=20(6)-1(6) and since it is easy to multiply 20 times 6 (=120) and 6 (-1) (=-6), we are left with 120-6 which is relatively easy to calculate in our head 120-6=114.
How can mental math be used to solve an equation?
Mental math is basically math in your head so for example 40x2=80 so I did that in my head
How do you use the distributive property to multiply 22x85?
22x85 = (20 + 2)x(80 + 5) = 20x(80 + 5) + 2x(80+5) = 20x80 + 20x5 +2x80 + 2x5 = 1600 + 100 + 160 +10 = 1870 Although if I were doing it in my head I'd probably just do 22x85 = (20 + 2)*85 = 20*85 + 2*85 = 1700 + 170 = 1870.
What is the distributive property of multiplication over subtraction using 65x39?
65*39 = 65*(40-1) = 65*40 - 65*1 = 2600 - 65 = 2535 To calculate 65*40 in your head, you can try 6.5 is half of 13 ie 6.5*2 = 13 so 65*2 = 130 so 65*4 = 260 and so 65*40 = 2600
