Multiplying with blocks: split into parts
Multiples of ten first, then a multi-digit number times a one-digit number with hundred, ten and one blocks: multiply each part and add.
- Germany: grade 3
- Iran: grade 3
- Russia: grade 3
Guide
Every number is made of hundreds, tens and ones. 213 is two hundreds, one ten and three ones.
To find 213 × 2, multiply each part by 2: 200 × 2 = 400, 10 × 2 = 20, 3 × 2 = 6. Then add: 426.
If a column has ten or more, exchange ten for one of the next place. For 4 × 30, multiply 3 tens by 4: 12 tens, which is 120.