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
Do the 2 x 50 first. Get 100. Multiply that by 14.
Move the decimal point two spaces to the right.
Multiply by ten and add one of the number. 7 x 11 = 70 + 7 23 x 11 = 230 + 23 = 253.
mentally solve whole number multiplication and division problems using: ... Dividing by 8 is like dividing by 2 then 2 then 2 so half 136 is 68 and half 68 is 34 and ... The following questions can be used to elicit discussion about the strategy
Rational?
Ooop
Assuming you meant 6 x 198... Do a mental sum for 6 x 200 (1200) then subtract 6 x 2 (12) to give you 1188.
You can do lattice, or do it mentally
26 x 26 = 26^(2) = 676 or 26 has the factors 2 & 13. so we can multiply 13 x 13 = 169 169 x 2 = 338 338 x 2 = 676 Or Long Multiplication 26 X 26 260 ( That is 26 X 10 ) 260 ( that is 26 x 10 again , making 20). 156 ( that is 26 x 6 = ) = 676 ===== or 26 x26 ===== 520 (26 X 20 = 520) 156 676 ====
Do the 2 x 50 first. Get 100. Multiply that by 14.
Move the decimal point two spaces to the right.
198 = (200 - 2) so use 6*200 - 6*2
Multiply the number by itself: 2x2=4, 3x3=9 and so on.
The term 'mentally' can simply be defined as of or relating to an individuals brain or mind. The word mentally is used in many different phrases just as 'mentally ill'.
Multiply by ten and add one of the number. 7 x 11 = 70 + 7 23 x 11 = 230 + 23 = 253.
Ramone had a well-researched strategy. Having a strategy is important. Ted used a time-tested strategy. The strategy is to stay on course.
de-centralized strategy